Researchers Test Disinfection of Patient-Care Items With UV-C


The near-patient environment is often heavily contaminated, yet the decontamination of near-patient surfaces and equipment is often poor. Moore, et al. (2012) conducted controlled laboratory studies to assess the  Nanoclave Cabinet's ability to eradicate a range of potential pathogens including Clostridium difficile spores and adenovirus from different types of surfaces. The Nanoclave Cabinet produces  large amounts of ultraviolet-C (UV-C) radiation (53 W/m2) and is designed to rapidly disinfect individual items of clinical equipment.
Each test surface was inoculated with known levels of vegetative bacteria (10^6 cfu/cm2), C. difficile spores (10^2-10^6 cfu/cm2) or adenovirus (10^9 viral genomes), placed in the Nanoclave Cabinet and exposed for up to 6 minutes to the UV-C light source. Survival of bacterial contaminants was determined via conventional cultivation techniques. Degradation of viral DNA was determined via PCR.

Results were compared to the number of colonies or level of DNA recovered from non-exposed control surfaces. Experiments were repeated to incorporate organic soils and to compare the efficacy of the Nanoclave Cabinet to that of antimicrobial wipes.
After exposing eight common non-critical patient care items to two 30-second UV-C irradiation cycles, bacterial numbers on 40 of 51 target  sites were consistently reduced to below detectable levels ([greater than or equal to] 4.7 log10 reduction). Bacterial load was reduced  but still persisted on other sites. Objects that proved difficult to disinfect using the Nanoclave Cabinet (e.g., blood pressure cuff) were  also difficult to disinfect using antimicrobial wipes. The efficacy of the Nanoclave Cabinet was not affected by the presence of organic  soils. Clostridium difficile spores were more resistant to UV-C irradiation than vegetative bacteria. However, two 60-second irradiation  cycles were sufficient to reduce the number of surface-associated spores from 10^3 cfu/cm2 to below detectable levels. A 3 log10  reduction in detectable Adenovirus DNA was achieved within 3 minutes; after 6 minutes, viral DNA was undetectable.
The researchers say that the results of their study suggest that the Nanoclave Cabinet can provide rapid and effective disinfection of some patient-related  equipment. However, laboratory studies do not necessarily replicate 'in-use' conditions and further tests are required to assess the  usability, acceptability and relative performance of the Nanoclave Cabinet when used in situ. Their research was published in BMC Infectious Diseases.

Reference: Moore G, Ali S, Cloutman-Green EA, Bradley CR, Wilkinson MAC, Hartley JC, Fraise AP and Wilson APR. Use of UV-C radiation to  disinfect non-critical patient care items: a laboratory assessment of the Nanoclave Cabinet. BMC Infectious Diseases 2012, 12:174.

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